INTRODUCTION: In cardiac imaging, respiratory motion causes image artifacts and ghosting. Over the past two decades, several approaches have been proposed to minimize motion artifacts such as breath-holding, respiratory navigators or self-gating [1]. In high resolution imaging, respiratory navigators using a 2D selective RF excitation typically positioned on the right hemi-diaphragm, have been ...

Let Z and IR (C) denote the ring of the integers and the field of real (complex) numbers, respectively. For a field F, we put i* = F\{0}. Fix A GC and B G C*, and let X(A, B) consist of all those second-order recurrent sequences {wn}neZ of complex numbers satisfying the recursion: n+i = „ ~ n-i (i.e., Bwn_Y = Awn wn+l) for n = 0, ± 1, ± 2,.... (1) For sequences in SE(A,B), the corresponding cha...

BACKGROUND Individuals with chronic diseases may have difficulty optimizing their health and getting the care they need due to a combination of patient, provider, and health system level barriers. Patient navigator programs, in which trained personnel assess and assist patients in overcoming barriers to care, may improve care and outcomes for patients with chronic disease by providing an altern...

PURPOSE To improve 3D volume-selective turbo spin echo (TSE) carotid artery wall imaging by incorporating navigators to reduce artifacts caused by swallowing. MATERIALS AND METHODS Images were acquired on a Siemens Magnetom Sonata 1.5T scanner. 3D volume-selective TSE scans of the carotid arteries were acquired in six healthy volunteers. A cross-pair navigator placed on the back of the tongue...

BACKGROUND Left ventricular (LV) torsion is an important indicator of cardiac function that is limited by high inter-test variability (50% of the mean value). We hypothesized that this high inter-test variability is partly due to inconsistent breath-hold positions during serial image acquisitions, which could be significantly improved by using a respiratory navigator for cardiovascular magnetic...

INTRODUCTION In dynamic echo-planar imaging (EPI), such as functional MRI, where a time series of EPI images are collected, there is additional modulation along echo readout due to changes in hardware states (e.g., temperature) that the standard reference scan based phase correction methods [1-3] cannot account for, thereby resulting in an increase of ghost level over time. To address this prob...

Background Advanced cardiac magnetic resonance (CMR) acquisitions often require long scan durations that necessitate respiratory navigator gating. This is particularly important in children with limited ability to hold their breath. We hypothesized that visual feedback of diaphragm position using an interactive videogame during CMR would increase navigator efficiency and improve image quality i...

BACKGROUND Cardiac and navigator-gated, inversion-prepared non-enhanced magnetic resonance angiography techniques can accurately depict the renal arteries without the need for contrast administration. However, the scan time and effectiveness of navigator-gated techniques depend on the subject respiratory pattern, which at times results in excessively prolonged scan times or suboptimal image qua...